#include<bits/stdc++.h>

using namespace std;
#define ll long long

const int N = 22, M = 55;
int T, n, m, vis[M], ans[M];
char a[N][M], b[N][M];
int main() {
    scanf("%d", &T);
    while(T--){
        scanf("%d%d", &n, &m);
        for(int i=1; i<=n; ++i) scanf("%s%s", a[i]+1, b[i]+1);
        memset(vis, 0, sizeof vis);
        for(int i=1; i<=m; ++i){
            ans[i]=0;
            for(int j=1; j<=m; ++j) if(!vis[j]){
                bool f=1;
                for(int k=1; k<=n; ++k) f&=a[k][i]==b[k][j];
                if(f){
                    vis[j]=1, ans[i]=j;
                    break;
                }
            }
            if(!ans[i]){
                puts("-1");
                goto nxt;
            }
        }
        for(int i=1; i<=m; ++i) printf("%d%c", ans[i], " \n"[i==m]);
        nxt:;
    }
    return 0;
}